Dear HYDRUS experts
I am trying to model water and solute transport in a silt loam soil irrigated via wicking from the bottom using HYDRUS 2D. I assigned var.flux2 bc for the wicking point at the bottom of the soil. I intended to simulate irrigation via wicking every 3 days [1 day irrigation via wicking, 3 days no wicking]. When there is a wicking, the flux is -86.035 cm/day and when is no wicking the flux is zero cm/day. However, when i run the calculation, hydrus did not give me any results. When i tried to changed the flux.var 2 to contast head of 3 cm, i obtained results. I red the manual, looked at the examples posted https://www.pc-progress.com/en/Default. ... cations#k3 and https://www.pc-progress.com/en/Default. ... d-lib-drip and i could not find a way to solve the problem. could you please help me to understand the problem and how to solve it?

I attached the hydrus file and an image to show you the domain and bc of my project

Dear prof
I tried to do 3 different things :
1. set a variable flux <ks for the soil
2. use the same value of the flux through all the simulation time. In this condition the variable flux is constant.
3. i was also suspecting that the problem could be due to the sign (-/+) of the flux although the manual said that "use negative values for inflow flux into the soil", so i tried to use both conditions one time simulation with positive flux and then another simulation with negative flux.
All trails did not work

I created a new project and attached here, maybe this could be more helpful to investigate the problem

Since you have infiltration into a very dry sand (note that the water content of a sand for the pressure head of -1000 cm is practically the residual water content) you need to allow smaller time steps. I have simply lowered the initial and minimum time steps and the program ran just fine. J.